In today's web, many services are available that enable users to build and share content among online communities. Some of these services are specific to particular types of content sharing, such as blogs and video or photo sharing services. Other services may be more general and aggregate a variety of services.
Social network services typically provide the ability to build and maintain online social networks for communities of people who share interests. Social network services typically include some form of directory and means for users within a social network to connect.
Directories typically include a list of people in a user's social network. Some directories may even be subdivided into categories of people, such as former classmates, co-workers, fellow club members, etc. The means to connect may include services such as instant messaging, email, video and voice chat, blogging and the like.
Social network services have revolutionized the ways in which we can communicate and share information with people from around the world. Social network services are used by millions of people every day, and have become part of the contemporary social fabric.